15 state-of-the-art quality assessment methods are selected for comparison, which consist of 8 FR-PCQA methods, 1 RR-PCQA method, and 6 NR-PCQA methods. The FR-PCQA methods include MSE-p2point (MSE-p2po) [1]}, Hausdorff-p2point (HD-p2po) [1]}, MSE-p2plane (MSE-p2pl) [3]}, Hausdorff-p2plane (HD-p2pl) [3]}, PSNR-yuv [5]}, PCQM [6]}, GraphSIM [7]}, and PointSSIM [8]}. The RR-PCQA method includes PCMRR [9]}. The NR-PCQA methods include BRISQUE [10]}, NIQE [11]}, IL-NIQE [12]}, ResSCNN [13]}, PQA-net [14]}, and 3D-NSS [15]}. Note that BRISQUE, NIQE, IL-NIQE are image-based quality assessment metrics and are validated on the same projected images.
Furthermore, to deal with the scale differences between the predicted quality scores and the quality labels, a five-parameter logistic function is applied to map the predicted scores to subjective ratings, as suggested by [16]}, [17]}.
